better handling of case where same genome has multiple annotation versions

[adf-ncgr]

currently, there's no very good way to support this. If you leave the chromosome ids unchanged, then you would end up getting chromosome with all annotations superimposed. When it has occurred in the past, I've just tweaked the chromosomes ids associated with one of the annotations, but as we begin to support genomic region linkouts, this becomes more problematic since the chromosome ids don't really exist outside of GCV. We do need to somehow internally treat them as distinct but they need to be able to reference the same external entity. It could get confusing to the user if the GCV labels used on the macrosynteny representation and track labels don't distinguish them too.